Low-power loss and highly efficient voltage converters, such as synchronous buck converters, are in demand for many applications such as mobile devices and other types of devices. As process technology advances, the tradeoff between efficiency and voltage ringing becomes more significant. Voltage ringing due to parasitics may require the choice of transistors for the converter to be rated for more than twice the voltage rating of normal operation.
One technique for addressing the efficiency problem (in which the converter itself consumes power) is to enhance the high side transistor switch of the buck converter as soon as possible to reduce voltage-current overlap losses. However, this approach results in parasitic inductance becoming excited with higher di/dt (rate of change of current) that causes high ringing in parasitic capacitors. In some examples, the peak voltage of the ringing can be twice (or higher) the input voltage of the converter. The rise time of the high side transistor switch can be reduced to reduce the ringing, but doing so results in increased losses and reduced efficiency.